Question: Is it possible to upgrade a part (such as the armrest) of this product?

Answer: Unfortunately, at the moment, it is not possible to upgrade or change the original parts of the chair.

Question: If this product is sold out, how long can it take before it gets back in stock?

Answer: This can depend on a variety of factors. Usually, an out-of-stock chair can take 1 to 3 weeks to restock. The best way to know when a chair is back in stock is to use the notification button on the product's page. This way, you are sure to not miss the next restock.